Among the many big issues Congress has on its plate -- immigration, sequestration and healthcare reform -- there are countless smaller battles waged between law makers. One of those battles is about eggs, and it has hatched into a much bigger debate over states' rights.

In 2010, California voters overwhelmingly passed Proposition 2, which set standards for how egg-laying hens could be raised. It requires hens have enough space in their cages to spread their wings.

Congressman Jared Huffman partnered with the Humane Society on the proposition.

“I ran my bipartisan legislation to make it very clear that this standard was uniform for all eggs sold,” Huffman says.

In other words, all eggs sold in California had to meet the standard. But opponents of the law argue that it shouldn’t apply to eggs laid outside California. Congressman Steve King of Iowa, the largest egg-producing state, proposed an amendment to the farm bill that would bar states from imposing their agricultural standards on other states.

“Congressman King’s amendment does not set a national standard for egg production,” says Mitch Head with United Egg Producers, a trade group that wants a national standard for raising hens. It believes a national standard would settle the issue once and for all and make it easier for all egg producers to comply with the law.

Where are all the other laws regulating crops and livestock? Check our map.